Many specialized commercial high volume container filling machines such as can or bottle fillers are in many ways unduly complex. This is especially true of container filling devices that dispense a flowable product into a container but which also must satisfy some additional constraint such as dispensing the product into the bottom of the container, keeping the dispenser submerged while dispensing, or precisely measuring the amount of product to be dispensed into containers. In general, increased complexity leads to increased costs associated with filling machine operation. Greater costs for such machines can be attributable to setting the desired positions of various assemblies for a given container to be filled. Difficulties can also arise in making adjustments during operation.
In a typical container filling machine there are a plurality of continuous cam tracks providing a predetermined path that is followed by a plurality of "filling stations" such that each such station is designed to fill a single container with each cycle through the cam track path. The cam tracks must be designed and adjusted for each container's dimensions. In connection with some filling machines there are various spring tensions or pneumatic pressures that must be maintained to properly dispense products into the containers.
In U.S. Pat. No. 3,189,062 of KaZmierczak a liquid bottle filler is disclosed with a plurality of filling stations for precisely filling bottles with a liquid substance. The apparatus disclosed includes five cam tracks, and, for each bottle filling station: four cam followers, at least two springs and a cylinder/piston dispensing combination. Of the four cam followers, one rides between two cam tracks and causes the product dispenser nozzle to be lowered to the bottle opening for product dispensing and raised once dispensing has been completed. One of the two springs, a compression spring, is used in conjunction with this follower to provide shock absorption as the dispenser descends to contact the bottle opening. The second spring, a tension spring, supplies a force to the filling station dispensing piston in a direction causing the surrounding cylinder to remain filled with the substance to be dispensed. In addition, this second spring also urges a pair of filling station cam followers against their related cam tracks. One of these tracks causes the dispensing piston to dispense the bulk of the product while the second track causes the piston to dispense precisely the amount required. Finally, a fourth station cam follower governs a valve allowing the product to flow into the bottle to be filled.
In U.S. Pat. No. 3,559,702 of Riesenberg a liquid bottle filler is disclosed such that the dispensing process results in minimal substance turbulence. More precisely, the Riesenberg apparatus fills bottles with a liquid product by inserting a filling stem into each bottle for dispensing the liquid near the bottom of the container and once there is sufficient liquid in the bottle, the stem outlet remains submerged while being slowly withdrawn from the bottle thus providing a smooth non-turbulent flow of liquid into the bottle. The filling controls for this apparatus consists of two cam tracks, and, for each bottle filling station contained in the apparatus: at least four pneumatic cylinders, three with positive pressure, one with negative pressure.
In U.S. Pat. No. 4,838,326 of Colacci et al. an apparatus is disclosed for dispensing a flowable product into containers at high speed as the containers travel in a straight line on an adjacent conveyor. Although no special constraints are imposed upon the dispensing mechanism, the apparatus still requires five cams tracks, numerous pneumatic cylinders to press the top cam track against the filling station cam rollers as they come in contact with this track. In addition, each filling station requires: two cam followers, a piston/cylinder dispensing combination and a latching mechanism to keep the filling stations tightly sealed to one another as they are filled with the product.
There are also well known apparatuses, called "bottom fillers," for dispensing a flowable or viscous product into the bottom of containers in a manner for reducing the development of air pockets in the container. Most bottom fillers require four circular cam tracks, and, for each filling station: two cam followers and a cylinder/piston combination for dispensing the product. For each filling station, the dispensing piston is surrounded by its sleeve or cylinder. The piston is allowed to reciprocate within the sleeve. Thus, the piston can be forced to retreat to one end of the sleeve as a pressured amount of product is allowed to fill the sleeve. Subsequently, the piston is forced in the opposite direction as the product is dispensed into the bottom of a container. The formation of air pockets is reduced in a container during the filling process since the sleeve can move independently of the dispensing piston and thus the product filled sleeve can be inserted into the bottom of the container prior to the piston expelling the product from the sleeve. Independent movement of the piston and the sleeve is achieved by the two pairs of cam tracks mentioned above. One pair is used to control the movement of each dispensing piston. The other pair is used to control the movement of each dispensing sleeve. For a given dimensioned container, each of the four tracks typically has a unique contour. Thus, substantial labor can be involved in initially positioning and/or subsequently adjusting all four tracks for appropriate container filling. Moreover, because the cam followers are sandwiched between tracks, such bottom fillers typically cannot easily provide a "no-container, no-fill" mechanism. That is, it is not feasible to stop the filling step when a can is missing because the four track configuration does not lend itself to such control
It would be advantageous to have container fillers that are both less complex to manufacture and require less labor to operate and maintain than those currently available. The present invention dynamically positions the dispensing mechanism within a container in a simple flexible manner. Embodied in an improved bottom filler, the apparatus requires only two cam tracks. One cam track for positioning the dispenser within the container and one cam track to cause an appropriate amount of product to be dispensed into the container. Furthermore, for each filling station, preferably a single pneumatic assembly supplies all the tension or pressure required for controlling the dispensing mechanism.